Katsuki and Izuku have lived in the same neighborhood since childhood and thus, were once childhood friends. Izuku looked up to Katsuki for his energy and confidence, while Katsuki himself often picked on him, giving him the demeaning nickname "Deku." After Katsuki gained his Quirk, however, his aggressive tendencies soon turned into heinous bullying; as he was constantly praised for his powerful Quirk, he developed a twisted superiority complex based on powers and thus looked down on Izuku for lacking a Quirk altogether. However, Izuku still considered Katsuki to be his friend, but things would escalate when Izuku tried to help Katsuki when he fell into a stream which Katsuki considered to be an insult, as he believed that Izuku made him look like he needed aid from someone who is beneath him.
Katsuki is in class while his teacher announces they all will graduate this year. Katsuki states that he's not like the other class members, calling them all fodder and that only he is destined to attend U.A., and he alone will surpass All Might. Once his teacher announces Izuku is attempting to get into U.A. as well, Katsuki is shocked and furious. He attacks Izuku, claiming that someone who is Quirkless cannot get into that school and can't do anything. After class, he takes Izuku's notes, blowing them up. He tells him that Heroes have had stories about them since their early school years, and only he is destined to reach that school and Izuku is just a stepping stone for his greatness. He then puts his hand on his shoulder (which is smoking) and tells him not to attend U.A.
Katsuki is later seen with other classmates wondering if he was too harsh on him but he ignores them stating he can't stand him for his optimism. Just then, a Villain (the same one All Might and Izuku met earlier) captures Katsuki and goes on a rampage. Katsuki tries to break free but is unable to. As people and Heroes are watching and unable to help him, Katsuki gives a pleading look and Izuku rushes to help him. While the latter demands why he's helping him, Izuku states he looked like he was needing help. The two are then saved by All Might. While Izuku is scolded for his recklessness, Katsuki is praised for his Quirk but the latter frowns in silence. Later, he finds Izuku stating he never asked his help and was fine all on his own and angrily storms off.When walking into the front of U.A., Katsuki sees Izuku also walking in. He confronts him by telling him to get out of his way and walks past him. Later in the auditorium in U.A., he sits next to Izuku and tells him to "shut it" because Izuku is yelling about Present Mic being Examiner. Katsuki then gets mad when Present Mic tells them that they can't attack other examinees, as he really wanted to crush Izuku. Later, during the Entrance Exam, Katsuki can be seen destroying multiple enemies. By the end results Katsuki was confirmed to have earned 77 villain points and scored the highest in that category. However, he received the lowest in rescue points, that being 0, and the only student to not get any rescue points.
Katsuki hears about Izuku being accepted into U.A. along with him which both shocks and angers him. He confronts him and demands what trick he used. He states he was supposed to be the only one from their school to attend U.A. and now his plan is ruined telling him to go to another school. Izuku, however, refuses, stating he found someone who believes in him and will not back down from him, shocking Katsuki since this was the first time Izuku ever stood up against him.
On the first day of class, Katsuki is arguing with Tenya Iida about having his feet on the desk but Katsuki doesn't care. When he asks where he went to school, Katsuki just states he's just another person to crush, shocking Iida who wonders if Katsuki is really trying to become a hero with that attitude.
Katsuki uses his quirk to launch a ball the farthest and become ranked on how long strong and how useful it is. He uses Explosion and launches it. When he sees Izuku Midoriya use his Quirk, he becomes shocked and furious, as he cannot believe that Izuku has a Quirk. He tries to attack Izuku out of anger, but Shouta stops him from doing so.
Katsuki is teamed with Tenya Iida as the villains team and assigned the mission to stop the heroes team consisting of Izuku Midoriya and Ochako Uraraka. Katsuki ambushes Izuku and uses Explosion on Izuku. Izuku grabs his arm and then throws him on the ground. After Izuku tells Katsuki that he has analysed and taken notes (the same notes Katsuki blew up and threw away in the past) on many Heroes including him. He announces that he is no longer the "Deku" who was a loser, but the "Deku" who's vibe is never giving up, much to Katsuki's fury.
Izuku tries to use the Capturing Weapon on Katsuki's leg, but Katsuki breaks free using his Quirk. Knowing he's at a disadvantage, Izuku retreats in order to think of a strategy.Afterwards, Katsuki finds Izuku and uses his bracer that has been storing up a lot of sweat to cause a huge Explosion, destroying a large portion of the building. However, Izuku manages to survive the blast and calls Katsuki insane for doing that, but a seathing Katsuki demands that Izuku use his Quirk.All Might tells Katsuki that if he uses another huge Explosion like that he will disqualify him and Tenya, much to Katsuki's anger, but decides to resort to fist fighting. Izuku and Katsuki continue theirfight, with Izuku trying to land a punch on Katsuki, but Katsuki launches himself behind Izuku using an Explosion and uses another Explosion to hit Izuku's back. Katsuki then hits Izuku's right arm, grabs it and throws him into the ground. Izuku is unable to think of a strategy in the midst of battle due to Katsuki not giving him any openings and realizes that Katsuki is simply far stronger than he is. Izuku decides to use his Quirk and informs Ochako to grab onto something. Instead of hitting Katsuki, Izuku aims his Detroit Smash into the ceiling, destroying the fifth floor's ground, but Izuku is forced to take the full brunt of Katsuki's Explosion. Although Izuku was unable to defeat Katsuki, it did distract Tenya long enough for Ochako to grab the fake Nuclear Bomb, allowing both Izuku and Ochako to win, shocking Katsuki.
Katsuki is in disbelief that he lost to Izuku. All Might approaches Katsuki, telling him that its time for his critique. He tells Katsuki that it doesn't matter whether he won or lost, but that he takes one look back, reflect on his experience and move on with life. Katsuki is seen outside school, but Izuku approaches him, telling him that he obtained his Quirk from someone else. Not believing him, Katsuki tells him that he lost fair and square and states to him that he still dreams of becoming the best of the best. All Might then appears before Katsuki, trying to counsel him on self-confidence, although he is told in response by Katsuki that he will surpass him as well, thus All Might decides to leave Katsuki alone.
Katsuki is approached by reporters, asking him if he is the boy from the sludge man incident, but he tells them to get out. Later, in class, Shouta Aizawa reprimands Katsuki, telling him to stop acting like a 7-year old as he is wasting his talent being like that. Shouta then announces that "unfortunately" they'll have to elect a Class President, surprising them but at the same time making them happy as U.A. "is finally starting to look like a school". Like most people, he voted on himself. At the end of the class elections, Katsuki is angered to see that people voted for Izuku.
Some days later, Shouta announces to Class 1-A that he, All Might and a third person will supervise them on a test of the abilities of the heroic foundaments, in Rescue Training. On the bus on the way to the U.S.J., Tsuyu says Katsuki won't be very popular because he's always stressed. After he realizes what she said, he screams at her in anger, effectively proving her point. He then listens expectingly to Thirteen's explanation about Quirks and the U.S.J., along with other students and Shouta.
When the villains appear at the U.S.J, Katsuki, along with Eijirou, tries to attack Kurogiri, but he uses his Quirk to warp them both to the Ruins Zone area of the U.S.J. Together, they easily defeat the villains there. He and Eijirou discuss what to do next, with Katsuki saying that he is going to fight Kurogiri since he is the villains' escape route. One of the villains try to attack Katsuki from behind, but Katsuki easily stops and defeats the villain. Katsuki is about to leave, but Eijirou decides to go with him having started to believe in him.
Katsuki then appears before Kurogiri, striking him with a punch and then restrains him. His effort along with Shouto allows All Might to escape from Noumu's clutches. Katsuki is forced to let go of Kurogiri when Noumu tries to attack him, evading him in the process. After the Villain Alliance is defeated, Katsuki is seen with his class.
Katsuki is seen confronting a crowd of students that is blocking his path, angrily telling them to go away, which angers one of the students from the General Education Department. On the day of the Sports Festival in the waiting room, Katsuki sees Shouto confront Izuku. After Izuku declares that he will do his best, Katsuki is seen grunting quietly. Katsuki then walks out with his class to the Sports Festival.
After being called to the stage as Class 1's representative, due to placing first in the Entrance Exam, he calmly declares that he will place first, which causes the classes from the other departments to rebuke at him. After the Obstacle Race starts, Katsuki avoids Shouto's ice and boosts himself ahead with his Explosion, using it to jump over the humongous robots and head to the next obstacle which is the Fall.
Katsuki manages to cross the Fall and after entering the land mine field, he blasts ahead to the lead with his Explosion since the land mines don't mean anything to him thanks to his Quirk and uses Blast Rush Turbo to propel himself forward, which allows him to catch up with Shouto who is in the lead. He asks Shouto if he issued his war declaration to the wrong rival. Both he and Shouto get into a brief scuffle for the lead position. Katsuki then watches Izuku flying towards him and Shouto. Izuku manages to pass them, which makes Katsuki angry. Katsuki manages to catch up to him, but Izuku uses his metal plate to blow dust into his eyes, stopping him momentarily, allowing Izuku to place first. Katsuki then crosses the finish line, placing third, allowing him to participate in the second event which is the Human Cavalry Battle but is angry that once again Izuku beat him. Many of his classmates want to team up with him for the Human Cavalry Battle, but he asks what their Quirks are (having seemingly forgotten), much to their surprise. Eijirou asks Katsuki to team up with him, saying that only he can withstand the recoils of his explosions and declares that they will get Izuku's ten million points, which sparks Katsuki's interest. Katsuki eventually teams up with Hanta and Mina as well.
After the Human Cavalry Battle begins, Katsuki jumps into the air and tries to attack Izuku with an Explosion, but Fumikage uses his Dark Shadow to block it. Hanta uses his Quirk to catch Katsuki so that he can land safely back on his team's formation. After Neito takes his headband without trouble and mocks him for always being attacked by villains every year, this makes Katsuki enraged and he then tells Eijirou that their plans have changed; before they take Izuku's ten million points, they will defeat Neito's team first.
Eijirou tells him that if he gets angry they won't be able to recover their points, but Katsuki says he's "madly calm". Katsuki battles against Neito but Neito copies and uses Katsuki's Quirk against him. Katsuki tries to attack Neito again, but Neito copies and uses Eijirou's Quirk to block him and shrugs him off. After Neito tells him not to become enraged since he fanned the flames, Katsuki says that he will be number one.
Katsuki jumps off his team's formation and attacks Neito. Kousei uses his Quirk to create a wall to block Katsuki. However, Katsuki punches through the wall and breaks it, grabbing two of Neito's headbands in the process, surprising Neito who could not counterattack due to having his guard down . Hanta uses his Quirk to reel Katsuki back onto their formation. Katsuki then orders his team to attack Neito; having Hanta use his Quirk and has Mina use her dissolving fluid. Katsuki and his team ride on Mina's fluid to reach Neito's team faster thanks to Hanta reeling in his tape.
Katsuki attacks Neito for the final time and grabs his last headband, which places their team at second place. Katsuki, however, wants to collect the ten million point headband and goes with his team to where Izuku's team and Shouto's team are. In the final ten seconds, Katsuki's uses his Quirk to launch off his team's formation and into the air. However, he has trouble deciding which team to attack and before he can come to a decision, the Human Cavalry Battle ends. Katsuki lands on the ground, annoyed that he could not get the ten million headband. However, Katsuki's last minute actions allowed him and his team to reach second place, allowing them to participate in the final event.
Katsuki is seen secretly overhearing Shouto explaining his story to Izuku, with a somewhat surprised expression on his face after hearing it. The final event is a tournament event and Katsuki's opponent in the first round is Ochako Uraraka, with Katsuki wondering who Ochako is. Katsuki watches Izuku's battle with Hitoshi and becomes nostalgic when Izuku throws Hitoshi over his shoulder, remembering that Izuku did the same action to him in the Battle Trial. After Denki says to Katsuki that Izuku used the same overthrow he used on him, Katsuki tells him to shut his mouth.
Katsuki walks to the ring to face his opponent, Ochako, in his first round match. Before the match begins, Katsuki tells Ochako that if she is going to withdraw, she should do it now. However, Ochako refuses to draw and the match begins; Ochako runs forward to attack and Katsuki retaliates by sending an explosion directly at Ochako which hits her. Katsuki, thinking Ochako is on the ground, grabs her, but sees that he has grabbed her jacket while Ochako sneaks behind him. Ochako prepares to attack him from behind, but Katsuki, seeing that she is behind him, uses an explosion against Ochako and blows her away, damaging her.
Ochako tries to attack him, however, Katsuki manages to be quicker than her and hits her with another explosion. Seeing that she is still standing, Katsuki attacks Ochako with two more explosions in an attempt to knock her out, but Ochako proves to be quite resilient (despite taking a huge amount of damage).
When Katsuki attacks Ochako with another explosion, the crowd start booing at Katsuki for toying with his opponent. However, Shouta defends Katsuki, saying that he is on guard and because he is doing everything to win, he cannot afford to let his guard down. Ochako, tired and battered by Katsuki's explosions, thanks him for being on guard as it allowed her to prepare her plan; to fire a shower of rubble against Katsuki (who never realized what she was doing) from above. The meteor shower of rubble descends on Katsuki while Ochako runs towards Katsuki. However, Katsuki creates a huge explosion which not only destroys the meteor shower of rubble but also blows Ochako back. Afterwards, Katsuki says to Ochako that he was aware that she was hanging around with Izuku and knew that she had something up her sleeve.
Katsuki prepares to attack her as he states that the real fight starts now, but Ochako collapses onto the ground, badly injured and drained of stamina due to Katsuki's attacks. Because Ochako is unable to move, she is declared defeated and Katsuki is declared the winner, thus he moves on to the next round.Katsuki leaves the ring and walks up the corridor where he sees Izuku. As Izuku tries to leave, Katsuki accuses Izuku of giving Ochako strategies to use against him, irritated that Izuku caused him trouble. However, Izuku replies that he didn't give Ochako any strategies and it was Ochako that devised the strategies herself to use against him, going on to say that if anyone was tossing him around, it was Ochako that was tossing him around, much to Katsuki's anger. He then goes to the stadium to sit with his class. As Hanta and Tsuyu comment on his match, Katsuki tells them to be quiet and goes to sit down on his seat. When Denki says that he was able to blast a frail girl with no qualms, Katsuki replies that there was nothing frail about her. As the match between Izuku and Shouto begins, Eijirou returns to sit down with his class. Eijirou tells Katsuki that he is next, to which Katsuki replies that he will beat him to death. After Eijirou states that both he and Shouto can send powerful attacks without breaking a sweat, Katsuki tells Eijirou that Quirks are physical functions similar to for example like running; if you run too much, you will run out of breath and as such Quirks have limits as well and comments that Shouto also has a limit to his Quirk.
Katsuki says to himself that he too has a limit on how much power he can use and as such is the reason why he added the Grenadier Bracers to his hero costume to amplify his Explosions. Katsuki continues to watch the battle between Izuku and Shouto. Katsuki notes that Shouto's movements have become sloppy, thinking that the reason behind it is because of his body's right side forming frost. Katsuki compares Shouto's ice limit to that of a video game's MP.
Katsuki faces his opponent, Eijirou, in his second round match. During the match, both Katsuki and Eijirou hit each other directly with their Quirks but Eijirou's tough skin dampens Katsuki's Explosion while Katsuki is injured by Eijirou's hardened punch. Katsuki evades Eijirou's hardened swipes unable to land an Explosion against him.
Katsuki eventually managed to hit and injure Eijirou with an Explosion. Katsuki realizes that Eijirou's Hardening weakens through continuous strikes. Katsuki attacks Eijirou with a continuous barrage of Explosions that not only breaks through Eijirou's Hardening but badly injures Eijirou as well. Eijirou is knocked out by Katsuki's Explosion barrage and Katsuki is declared the winner, allowing him to advance to the third round (semi-finals).
Katsuki faces his opponent, Fumikage, in his third round match. Katsuki's fierce fighting style and Quirk type advantage force Fumikage to go completely on the defensive, not even giving Fumikage any room to counter. However, Fumikage's Dark Shadow does keep Katsuki at bay which annoys Katsuki. After hitting Dark Shadow with two Explosions, Katsuki jumps into the air and lands another Explosion on Dark Shadow. Fumikage orders Dark Shadow to grab Katsuki, but Katsuki counters Dark Shadow with an Explosion which stops Dark Shadow. Katsuki leaps over Dark Shadow and gets behind Fumikage. Katsuki prepares to a move called Stun Grenade as Dark Shadow tries to protect Fumikage. However, Katsuki successfully executes Stun Grenade before Dark Shadow gets into a defensive position. Thus, Katsuki's Stun Grenade effectively hits Dark Shadow and Fumikage. After the smoke clears, Katsuki has pinned down the injured Fumikage. Katsuki tells Fumikage that it's his fault for telling people about Dark Shadow's weakness but admits that it wasn't a fair matchup to begin with. Fumikage surrenders, making Katsuki the winner and allowing him to advance to the final round where he will face Shouto Todoroki.
After his match with Fumikage, Katsuki barges into a waiting room but finds out that he entered the wrong room. Katsuki sees his opponent, Shouto, waiting in the room. Shouto doesn't pay much attention to Katsuki, much to Katsuki's annoyance. Katsuki complains about Shouto's attitude towards a fellow finalist. Shouto continues to ignore him until Katsuki uses a small Explosion on the table to get his attention. Shouto says to Katsuki that Izuku is the type of person who is compelled to drag out peoples' problems and help them. Shouto asks Katsuki, as Izuku's childhood friend, if Izuku has always been the type of person compelled to help people's problems. Katsuki remembers how Izuku tried to help him in their childhood, which infuriates Katsuki. Furious, Katsuki angrily kicks the table over, telling Shouto that he doesn't care about Izuku and doesn't care about Shouto's problems or feelings. Before he leaves, Katsuki tells Shouto to give everything he's got and as he walks out of the waiting room, Katsuki says that he will make Izuku bow to him once he has reached the top.
Katsuki faces his opponent, Shouto, in the final round. As the match begins, Katsuki grins with satisfaction as after his match with Shouto he says that he is going to be the best. The final match begins with Shouto attacking Katsuki with a huge pillar of ice. However, Katsuki thaws himself out with an Explosion. After breaking out of Shouto's ice, Katsuki uses some Explosions to somersault himself into the air. While in the air, Katsuki grabs Shouto's hair and shirt and throws Shouto onto the ground, but Shouto creates an ice wall behind himself to prevent himself from being thrown out of the ring. Katsuki immediately attacks Shouto with an Explosion, but Shouto grabs Katsuki's arm, throws Katsuki into his wall of ice and in the process throws himself out of Katsuki's way. Katsuki becomes angry at Shouto for not using his full power and yells that there is no point in beating anyone if they don't use their full power. Katsuki says that he can't prove himself if he defeats Shouto too easily and tells Shouto to not stand in front of him if he doesn't plan on fighting to win. Katsuki dashes into the air and creates two explosions in his hands. He spins himself around and after doing so, Katsuki attacks Shouto with his move Howitzer Impact; an explosive tornado which hits Shouto. Katsuki lands on the ground after using Howitzer Impact. Katsuki sees that Shouto is out of the ring. Furious, Katsuki immediately gets up and grabs Shouto by his shirt, dissatisfied with Shouto's performance. Before he can do anything, Katsuki is knocked out by Midnight's perfume. Because Shouto went out of bounds, Katsuki is declared the winner of the final match and due to winning the tournament event, Katsuki is also the winner of Class 1's Sports Festival.
At U.A.'s closing ceremony, Katsuki is on the podium for his first place award. However, due to being furious at Shouto and to prevent him from unleashing his fury at him, Katsuki is fully restrained; his arms and hands restrained with locks, his body wrapped around a wooden log, chained to the podium and a face mask. All Might goes to Katsuki to give him his medal for achieving first place and while taking off his face mask compliments him on his foreshadowing. Katsuki angrily tells All Might is an expression of fury that he doesn't deserve to be Number One as he doesn't acknowledge it. All Might tells Katsuki that society will still acknowledge him as being worthy of Number One even if he doesn't. All Might gives Katsuki his medal but Katsuki instead angrily grabs it by biting it.
After the closing ceremony of U.A.'s Sports Festival is finished, later the next day at noon, Katsuki is at home angrily brushing his teeth, still unable to let go of his fury.
Two days after the Sports Festival, Katsuki is in class. During the Hero Informatics period, Shouta shows the Pro Hero nominations which reveals that Katsuki received 3,556 Pro Hero nominations the second highest in the class. Afterwards, Class 1-A has to decide on Hero names. Katsuki writes down Explode Kill King (爆殺王 Bakusatsu Ō?). However, Midnight asks him to change his name. As Katsuki changes his Hero name, Izuku reveals his Hero name to be Deku which makes Katsuki angry. After Izuku is finished presenting his Hero name, Katsuki changes his Hero name to Explode Kill Lord (爆殺卿 Bakusatsu Kyō?), to which Midnight replies that it won't do either.
After Class 1-A is finished formulating their Hero names, Shouto is given his personalized work place list in order to choose a workplace that he wants to train at. Katsuki becomes irked from Izuku and Ochako's constant talking. On the day of the work place training, Katsuki is at the train station with his class so that he can travel to the work place of his choice by train.
Katsuki arrives in the Tokyo metropolitan area and goes to his workplace. Katsuki's workplace of choice is revealed to be the Best Jeanist's hero office. In the office, Best Jeanist deduces that Katsuki chose him and his office because he ranks among the top five Heroes. Katsuki replies that he nominated him, to which Best Jeanist says he did since the other candidates have been good kids and it has been a while since someone like Katsuki has come along, telling Katsuki that reforming brutish people is what he does as a Hero. Best Jeanist tells Katsuki that he will show him what it is that makes people Heroes.
After Stain's defeat is published, the incident that occurred with the Hero Killer is on Katsuki's mind; Best Jeanist states that the incident is also on his mind, but they must remain calm and collected; Best Jeanist tells Katsuki and his sidekicks that they will be running things smoothly as usual.
The workplace training ends and Katsuki returns to U.A.. In Class 1-A, Eijirou and Hanta laugh at Katsuki's new hairstyle (courtesy of Best Jeanist), causing Katsuki to retaliate in anger at them. During Foundational Hero Studies, Katsuki notes that Izuku will lose. Katsuki watches the race and becomes shocked that Izuku's movements resemble his own. Katsuki becomes angry that Izuku has improved so much within one week while he had been doing nothing.
One week before the end of term test, in class, Eijirou notes that Momo is being virtuous to which Katsuki angrily reminds him that he is also virtuous, saying that he will tutor him until he bleeds (since he has the third highest grade in the class). After lunch, Izuku reveals the contents of the exercise test; Katsuki says that he doesn't care about who he will be fighting in the exercise test since his opponents will be blown away in the end. Angry, Katsuki confronts Izuku, saying that Izuku is starting to get on his nerves. Ochako wonders if Katsuki is referring to Izuku's movements during the Foundational Hero Studies. Katsuki says to Izuku that he doesn't want the same hollow result like the Sports Festival. Katsuki says that they will determine who is the better man by their grades; Katsuki remarks that he will show the power gap between them and defeat him. Seething, Katsuki says that he will also defeat Shouto as well. Katsuki storms out of the classroom. Eijirou notes that Katsuki hasn't been agitated in a while to which Fumikage says that Katsuki's animosity is getting the better of him. While Katsuki walks through the corridor, Shouta notes that Katsuki has become worse.
On the day of the exercise test, Mr. Principal reveals that Class 1-A will be fighting U.A.'s teachers in their exercise test. Shouta says that Izuku and Katsuki will be paired together, much to their shock. Izuku and Katsuki become more surprised to learn that they will be facing All Might in combat for their exercise test. All Might tells the duo to cooperate together to defeat him.
All Might, Izuku and Katsuki get onto a bus and drive to an uninhabited city where the test exercise will take place. All Might, Izuku and Katsuki arrive in the city. All Might explains the test exercise: Izuku and Katsuki have two options of winning and passing the test exercise; they must either handcuff All Might or one of them must escape from the battlefield. Izuku and Katsuki have to accomplish either fighting to handcuff their opponent or one of them must escape the battlefield in 30 minutes. Izuku notes that this will test their flight or fight decision skills. All Might puts on super compact weighted bracelets to give himself a handicap. The test exercise begins. Katsuki decides to fight All Might in order to handcuff him while Izuku suggests that avoiding the fight with All Might and escaping is a better course of action. Katsuki ignores Izuku's suggestion and begins going toward All Might. Izuku tells Katsuki that the idea of him beating All Might is ludicrous. Katsuki smacks Izuku onto the ground; Katsuki angrily orders him to stop talking while Izuku says that he is talking because he wants them to pass. Izuku and Katsuki get into an argument; Katsuki declares that he can pass the test himself and didn't need Izuku's help in the first place while Izuku says that Katsuki's bad anger is the reason nobody likes him. Suddenly, All Might throws a punch which devastates the area Izuku and Katsuki are in.
All Might declares to the duo that he is a villain and collateral damage means nothing to him. All Might charges at the duo. Feeling All Might's pressure, Izuku tells Katsuki that they have no chance of winning and should run away. However, Katsuki refuses to run away. Katsuki uses Stun Grenade against All Might which distracts him. Katsuki charges at All Might but the Symbol of Peace grabs Katsuki's face, stopping his advance. Katsuki launches a flurry of Explosions against All Might. However, Katsuki's Explosions do not even scratch All Might. All Might slams Katsuki down onto the ground. All Might turns his attention to Izuku who planned on running away. Izuku jumps into the air, but Katsuki has also jumped into the air; the duo collide into each other as a result. After the recoil, Izuku begs Katsuki to escape with him as they have no chance of winning. Angry, Katsuki still refuses to escape, saying that he will win because that is what a Hero does. Izuku remembers Katsuki's past; that he admired All Might as a Hero because he always won in the end regardless of the situation he was in.
Izuku tries to convince Katsuki otherwise but to no avail. Suddenly, All Might appears in the air with a guardrail in his hands; All Might slams the guardrail on Izuku which pins him down to the ground. Then, All Might punches Katsuki in the stomach, greatly injuring him and sending him flying backwards. All Might approaches Katsuki and says that he understands his jealousy of Izuku's sudden growth; All Might tells Katsuki that what he is currently doing is a waste and he must grow his willingness to borrow other peoples' strength when needed. The weakened Katsuki struggles to get up and tells All Might that if he must rely on other peoples' strength, then he would rather lose. Disappointed with Katsuki's decision, All Might prepares to finish off Katsuki; Katsuki tries to move but to no avail. Suddenly, Izuku breaks free of the guard rail; Izuku charges and punches Katsuki out of harms way. Izuku grabs Katsuki and leaps into an alley to escape from All Might. Izuku tells Katsuki to not say that he would rather lose, asking Katsuki to use his strength before giving up and reminds Katsuki that he is the kid that never gives up on winning. In their childhood, Katsuki manages to beat 4th graders and says that the Number One Hero always wins in the end while Izuku admiringly looks on.
All Might chases after Izuku and Katsuki. Suddenly, Katsuki appears from behind and attacks All Might with an Explosion which distracts All Might. However, one of Katsuki's Grenade Bracers is missing. Suddenly, Izuku appears behind All Might with Katsuki's missing Grenade Bracers equipped on him. Katsuki yells at Izuku to commence his attack; Izuku aims the Grenade Bracer at All Might and releases the grenade pin.
Izuku releases the grenade pin and blasts an immense Explosion at All Might at point blank range. After the Explosion is finished, Izuku and Katsuki dash towards the exit.
However, All Might catches up to Katsuki and Izuku and defeats them; All Might apprehends Katsuki by pinning him down with his foot.
A minute ago, Izuku and Katsuki are running towards the escape gate after blasting All Might with an immense explosion. Izuku spots the escape gate and notes that if one of them passes through the escape gate they pass the practical test. While running, Izuku isn't able to see All Might and wonders if he fainted, to which Katsuki admonishes Izuku for thinking that way. Katsuki tells Izuku that if All Might catches up he will launch Izuku using his bracer. Suddenly, All Might appears before the two, asking Katsuki what he plans to do after that, shocking Izuku and Katsuki. Before the young heroes can react, All Might crushes Katsuki's Grenadier Bracers into pieces, telling the duo that the weights are forcing him to use only a minuscule of his strength; All Might proceeds to pin down Katsuki with his foot and dangles Izuku in mid-air.
Back in the present, Recovery Girl announces that Shouto and Momo are the first team to pass the exam. All Might is surprised to learn that his colleague, Shouta, has been defeated. All Might smashes Katsuki into the ground with his foot. Katsuki finally understands that All Might is far too overpowered for him to stop and realizes that All Might is truly the strongest Hero and the world's most sky scrapping wall. All Might decides to finish off Izuku and Katsuki.
Suddenly, Katsuki gets up and launches a big explosion against All Might, which distracts the Symbol of Peace. While All Might is distracted by the light, Katsuki grabs Izuku and throws Izuku towards the escape gate with an Explosion. To prevent Izuku from escaping, All Might uses New Hampshire and blasts himself into Izuku which crushes Izuku due to All Might's great weight and sends him tumbling down. Katsuki chases after All Might; Katsuki tells All Might that the Grenadier Bracers were to help him use his maximum Explosions without risk and admits that he was a fool for thinking that he could win without taking risks. Katsuki uses a huge Explosion against All Might (similar to the Explosion in the Sports Festival) and tells Izuku to escape; Izuku struggles to get up. Katsuki decides to sacrifice himself to hold off All Might so that Izuku has time to escape; Katsuki uses another huge Explosion against All Might. However, although the great Explosions have distracted All Might, the Symbol of Peace is still unscathed.
Izuku gets up and prepares to activate One For All Full Cowl so that he can leap towards the escape gate. Not allowing Izuku to make an escape, All Might prepares to attack Izuku but Katsuki intercepts All Might's attempt. Izuku successfully activates One For All Full Cowl and begins his escape while All Might smashes Katsuki into the ground. Izuku sees that Katsuki is in trouble. Despite being greatly injured, Katsuki yells at Izuku to escape and bites All Might's hand. All Might ignores Katsuki's desperate attempt and tells Izuku that he won't allow him to escape.
Surprisingly, Izuku does not rush towards the escape gate; instead, Izuku rushes back to help Katsuki. Izuku smiles and punches All Might in the face. While All Might is suffering from slight recoil, Izuku grabs Katsuki who has fallen unconscious. Izuku rushes towards the escape gate with Katsuki in tow. All Might shrugs off Izuku's punch and watches him escape. Izuku passes through the escape gate along with the unconscious Katsuki in tow, which allows Izuku and Katsuki to pass the practical test.
After Izuku and Katsuki pass the practical exam, All Might carries them to Recovery Girl's tent to be healed. Recovery Girls scolds All Might for not restraining himself during his battle with Izuku and Katsuki. Recovery Girl asks All Might to take Izuku and Katsuki back to U.A. to recover. After Izuku requests to stay, All Might leaves carrying an unconscious Katsuki in his arms, he notes that Izuku will be extraordinarily strong one day. All Might walks out of the tent and prepares to carry Katsuki back to U.A.. All Might notes that Katsuki himself is also incredible and that whenever there is a wall in front of Katsuki, he laughs at it.
Back in class at U.A., Katsuki learns that he has passed the written test and will go along with his classmates to the forest lodge which is a boot camp. After Class 1-A decide to go shopping to buy necessities for the boot camp, Katsuki declines to go with.
The next day at U.A., Shouta informs Class 1-A that the destination for their lodge trip has been changed and the new destination will only be announced on the day of the event. During class, Katsuki criticizes Izuku for not trying to attack the villain holding him hostage. The first semester has come to a close and summer break has begun.
On the day of the event, Class 1-A boards a bus that will take them to the forest lodge destination. An hour later, Class 1-A’s bus stops for a restroom break. However, Class 1-A notes that Class 1-B isn’t at the rest stop. Suddenly, two females wearing cat-like costumes and a small boy appear; the females excitedly introduce themselves as the professional Hero Team, The Pussycats. Mandalei explains to Class 1-A that they will be staying at the base of a mountain which is a part of their domain; they have three hours to reach the base of the mountain using their Quirks as they please and those who don’t arrive there by 12:30 pm won’t be served lunch. Soon, Class 1-A realize that they have already arrived at their destination and their training camp has already begun with the Pussycats being their supervisors. Some of Class 1-A try to leave, but Pixiebob uses her Quirk to create a landslide of dirt that causes Class 1-A to fall into a forest called Forest of Magic Beasts, which they must traverse to reach their destination. Suddenly, Class 1-A are confronted by a beast; Kouji tries using his Quirk to control the beast but it does not work due to the beast being made out of dirt. Katsuki along with Shouto, Tenya and Izuku mobilize and use their Quirks to destroy the dirt beast.
After Izuku, Tenya, Shouto and Katsuki destroy the dirt beast, Class 1-A begins traversing the Forest of Magic Beasts. However, the journey through the forest to the Cabin takes around about 8 hours. Class 1-A arrive at the facility, battered and tired. It is now 5:20 pm in the evening. Pixiebob admits that she thought they would take longer to get to the facility; she praises Class 1-A for figuring out her Earth Beasts quickly and easily. Pixiebob then commends Izuku, Tenya, Shouto and Katsuki for taking quick action against one of her Earth Beasts and concludes that they have experienced action against villains. After Kouta punches Izuku in his crotch and harshly replies to Tenya, Katsuki comments that Kouta thinks he is an adult; Shouto replies that Kouta reminds him of someone who also acts like an adult (referring to Katsuki himself). Katsuki tells Shouto that he doesn't keep his emotions bottled up like someone he knows (referring to Shouto) while Shouto replies that he was joking.
Class 1-A fetch their luggage and put it in their rooms, Class 1-A head to the dining hall and have dinner; they enjoy the delicious food that the Pussycats provide them. After finishing dinner, Class 1-A go to the hot springs.
The next day at 5:30 AM, Class 1-A are outside the training camp cabin. Shouta greets his students and tells them that they will undergo reinforcement training to strengthen and upgrade their Quirks which will also allow Class 1-A to obtain their temporary licenses. Shouta tells Katsuki to perform the pitch from the Quirk Apprehension Test. Katsuki throws his pitch; however, Katsuki’s pitch records at 709.6 m, which is a minor increase from his last pitch. Some of Class 1-A are surprised with the lack of difference with Katsuki’s new pitch as they were expecting it to be immensely higher. Shouta explains that while Class 1-A has grown emotionally and technically, their Quirks have not which is why they are having the training camp to upgrade their Quirks.
Katsuki trains along with the rest of his class. Later that day at 4:00 PM, Pixiebob and Ragdoll provide Class 1-A food materials and tell them that they must make their own food from now on. Tenya sees this as survival skill training and motivates his class to start making curry. Class 1-A begin making their own curry and after doing so, eat it for dinner. On the third day, Katsuki continues his training along with his class and Class 1-B.
Later that night after dinner, Katsuki is paired with Shouto for the test of courage. A few minutes after entering the forest, Yui tries scaring Katsuki and Shouto, although to no avail. Suddenly, the League of Villain's Vanguard Action Squad attacks. Shouto (while carrying an injured Kousei Tsuburaba) and Katsuki run through the forest. Seeing that the situation is chaotic, Shouto decides that they should head back to the facility to regroup. While running to the facility, Shouto and Katsuki encounter a villain; Katsuki asks Shouto who is supposed to be ahead of them, to which Shouto answers Fumikage and Mezou. The villain is admiring something on the ground; a severed arm. However, the villain realizes he has work to do and cannot afford to be distracted by the severed arm; the restrained villain turns his attention to Katsuki and Shouto.
Shouto engages in combat with the restrained villain (known as Moon Fish), using his ice to block the villain’s teeth enlarging Quirk. Moon Fish proves to be highly skilled, being able to break through Shouto’s ice and nearly hit Katsuki with one of his teeth, only to be intercepted by Shouto’s ice. Shouto warns Katsuki to not use his Explosion Quirk due to the fear of igniting the poisonous gas and causing more chaos, much to Katsuki’s annoyance. Moon Fish continues breaking through Shouto’s ice defenses with his teeth enlarging Quirk while also using his teeth to maneuver himself around.
Shouto and Katsuki continue their battle with Moonfish; Shouto is unable to fight properly due to carrying Kousei. The Shouto tries his best to keep Moonfish at bay by blocking his path with ice. Katsuki becomes furious that he is unable to fight back, thinking that firing a huge explosion should stop Moonfish, but Shouto warns Katsuki that the huge explosion will limit their visibility and give the villain more attacking opportunities. When Mezou and Izuku arrive to Katsuki and Shouto's location, Mezou asks one of them to make light. Before he can explain further, Moonfish senses Mezou and Izuku’s presence and sends one of his teeth to attack them. Suddenly, the rampaging Dark Shadow appears and uses its enormous claw to crush Moonfish, destroying Moonfish’s teeth. Shouto and Katsuki are surprised at what transpired.
After the rampaging Dark Shadow effortlessly defeats Moonfish, Katsuki and Shouto manage to get close to Fumikage and use their Quirks, which calms down Dark Shadow; Dark Shadow reduces in size and retracts back into Fumikage, allowing Fumikage to return to normal. Katsuki once again tells Fumikage that their Quirks have a bad chemistry; Fumikage thanks Katsuki for saving him. Izuku tells Fumikage that their top priority is to protect Katsuki, who is the target of the villains’. Izuku decides that they should escort Katsuki back to the facility and take a shortcut through the forest to do so; Izuku thinks that with the power of Mezou’s scouting capabilities, Shouto’s powerful Quirk and the unrivaled power of Fumikage’s Dark Shadow, escorting Katsuki will be a cinch. However, Katsuki is angry that he needs protecting and refuses their help. The Bakugo Escort Squad (consisting of Mezou, Shouto, Izuku and Fumikage) begin escorting a begrudging Katsuki back to the facility.
The Bakugo Escort Team travel to the facility and come across Ochako and Tsuyu. After seeing that Ochako and Tsuyu are alright, Izuku asks them to join the escort. However, Ochako and Tsuyu wonder why Katsuki isn’t with them. Mezou, Shouto and Izuku turn around only to find that Fumikage and Katsuki are missing.
Suddenly, a masked villain appears on a tree branch and reveals that he used his “magic” to take Katsuki by turning him into a marble. The masked magician-like villain, known as Mr. Compress, states that the Heroes don’t deserve someone of Katsuki’s caliber and notes that Katsuki will shine even brighter on the villains’ side. Izuku demands that he give Katsuki back. Izuku, Mezou and Shouto chase after Mr. Compress in order to rescue Fumikage and Katsuki.
At the Vanguard Action Squad's rendezvous point, thanks to Yuuga firing his Navel Laser at Mr. Compress, Katsuki's compressed form is released from Mr. Compress's grasp. Shouto tries grabbing Katsuki, only for Dabi to snatch Katsuki away. Dabi orders Mr. Compress to deactivate his Quirk, to which he does. Katsuki is freed from his marbled prison but is grabbed on the shoulder by Dabi to prevent him from escaping. Izuku desperately tries rescuing Katsuki but to no avail. Before warping away with Dabi, Katsuki tells Izuku to stay back. The warping completes and the captured Katsuki teleports away along with the Vanguard Action Squad.
Inside the League of Villains’ hideout, Katsuki is strapped and restrained on a chair being surrounded by members of the Vanguard Action Squad, Kurogiri and Tomura. Tomura asks Katsuki to become his ally, but Katsuki vehemently tells him to drop the small talk and die.
After Katsuki and the League of Villains watch a video clip of U.A.'s public apology, Tomura understands why society is blaming U.A. for their failure and that is because the current Hero society is not just. Spinner agrees that the current Hero society isn’t just since the modern Heroes are only doing their job for compensation and not out of selflessness. Tomura explains that the League of Villains are fighting for a just society and intends to win this battle. Tomura orders Dabi to remove Katsuki’s restrains, although Dabi is unsure since Katsuki might attack; Tomura wants to treat Katsuki as an equal and is aware that Katsuki knows he has no possibility of winning. Dabi has Twice remove the restrains. As Twice removes the restrains, Mr Compress apologizes to Katsuki for forcibly kidnapping him and explains that the League of Villains are not just a group of hoodlums perpetuating crimes nor did they casually abduct him; he goes on by saying that everyone in the League of Villains is shackled by the current society and hopes that Katsuki understands their discrimination.
Katsuki’s restrains are removed. As Tomura approaches Katsuki, Katsuki attacks Tomura with his Explosions. Katsuki tells the League of Villains that it is pointless to try and make him change his mind as he has already been won over by the way All Might looks when he wins. Katsuki says that from the beginning he has dreamed of becoming a Hero and surpassing All Might and nothing they say will change that.
After hearing Shouta state that Katsuki desires to be a Hero, Katsuki tells his captors that U.A. are correct about him desiring to be a Hero. Katsuki taunts the Vanguard Action Squad and Tomura, telling them that his combat authorizations have not been revoked. However, Dabi, Himiko, Kenji and Mr. Compress are not intimidated; they wonder about Katsuki’s mental state and conclude that he has messed up by going against them. After picking up his hand, Tomura decides that he must use force on Katsuki and asks his teacher, Sensei, to help him do so.
Tomura orders Kurogiri and Mr. Compress to knock out Katsuki. Katsuki continues insulting the League of Villains while thinking of a way to cause a distraction that will allow him to make a run for the door behind him.Suddenly, All Might breaks in with Kamui Wood swinging in and restrains the League of Villains with his Lacquered Chains Prison. All Might checks on Katsuki and compliments him for not being afraid, much to Katsuki's chagrin.
As Gran Torino and All Might attempt to get information about Sensei from Tomura, mysterious black liquid appears with dozens of Noumus appearing out from the phenomenon. All Might grabs hold of Katsuki. Suddenly, Katsuki is engulfed by the black liquid and dissolves into it, much to All Might's fury.
Katsuki is teleported by the mysterious black liquid to Sensei's location which is near the ruins of the League of Villains' warehouse. Sensei apologizes to Katsuki as Tomura, Kurogiri and the Vanguard Action Squad finish materializing from the black liquid's teleportation.
All Might appears and clashes with Sensei. After All Might is blasted away, Katsuki becomes concerned, but Sensei tells Katsuki not to fret since his blast wave attack isn’t strong enough to kill him. Sensei uses a Quirk to forcefully activate Kurogiri's Warp Gate Quirk, causing a portal to appear and instructs the League of Villains to leave with Katsuki. However, Katsuki isn't willing to give himself up so easily and prepares to battle the League of Villains. Katsuki fends off Himiko, Twice and Mr. Compress with his Explosions; All Might tries to help Katsuki only for Sensei to intervene.
During the battle, Izuku, Tenya and Eijirou appear in the air from above. Katsuki sees the trio while Eijirou yells at Katsuki to take his hand. Tomura tries to take Katsuki, but Katsuki uses his Explosion to launch himself towards Izuku, Tenya and Eijirou. Katsuki grabs Eijirou’s hand and smiles.
Kenji and Spinner launch Mr. Compress into the air, but Mount Lady intercepts him, allowing Izuku along with Eijirou, Tenya and the rescued Katsuki to get away. Izuku, Eijirou, Tenya and Katsuki land on the ground far from the battlefield and begin escaping.
Katsuki manages to escape to the front of the train station. He and Katsuki converse, with Katsuki stating that he wasn't rescued and that he only escaped with them so that he wouldn't get in All Might's way. Katsuki watches the broadcast of the battle between All Might and Sensei and becomes surprised upon seeing All Might's true form. Many civilians encourage All Might to win, with Izuku and Katsuki also encouraging him.
After the battle between All Might and All For One, Izuku and his group meet up with Shouto and Momo. They take Katsuki to a Police Station for his safety.
The Police Force take Katsuki back home. Shouta and All Might visit is the home of Katsuki Bakugo. Inside the Bakugo household, Katsuki’s mother agrees to the U.A’ students’ relocation, being more than happy to send her son away. Katsuki and his mother begin arguing with each other while Katsuki’s father tries to calm them down. After calming down, Katsuki’s mother notes that Katsuki’s rashness along with his gifted abilities,has resulted in him being pampered and getting shallow praise for what he has which has resulted in his arrogant nature. However, Katsuki’s mother is happy that Shouta sees her son for who he is instead of his gifted abilities. Katsuki’s mother once again agrees to leave Katsuki in U.A’s care since her son returned home safe and sound thanks to the Pro Heroes and asks Shouta to make her son into a fine Hero.
As Shouta and All Might leave the Bakugo household, Katsuki asks All Might what Izuku is to him. Unable to tell Katsuki the truth, All Might informs Katsuki that Izuku is a student to him who has great potential just like Katsuki. Satisfied to a degree with All Might’s answer, Katsuki thanks All Might for everything and goes back inside his house.